JBIS: Celebrating the ‘Red Cover’ Issues

by Paul Gilster on May 13, 2011

Working on a book on interstellar flight in 2002, I came across a paper in the Journal of the British Interplanetary Society with a bold title: “A Programme for Interstellar Exploration.” I already knew that its author, Robert Forward, was a major figure in the world of deep space studies, an aerospace engineer and inventor with a deep knowledge of physics as well as a popular science fiction author, in whose stories many of his futuristic ideas were played out. What I didn’t know until I read the paper was that this man had proposed a step-by-step plan for reaching the stars way back in 1975 at a meeting at the U.S. House of Representatives.

These were bold years for interstellar thinking, as witness Forward’s appearance before the Subcommittee on Space Science and Applications that year. Forward developed a fifty-year plan for interstellar exploration that, in his words, ‘envisions the launch of automated interstellar probes to nearby stellar systems around the turn of the century, with manned exploration commencing 25 years later.’ He went on to discuss five possibilities for interstellar propulsion systems based on a series of projections of technology programs in nuclear fusion, particle physics, high-power lasers and thermonuclear explosives. Imagine Forward telling these political leaders that a manned starship might embark for Alpha Centauri by the year 2025.

A Home for Visionaries

It all seems a bit surreal, given what has happened to our space plans after Apollo, but Forward’s paper on these matters in JBIS is still lively reading, and so is another interstellar program put forward by Michael Michaud, then an official with the U.S. State Department. Michaud’s plan discussed the possibilities of interplanetary exploration and moved into the interstellar realm by envisioning a search for extrasolar planets (at the time, of course, we knew of none). His closely reasoned program for colonizing the Solar System would in his schedule be followed by the first star probes using fusion technologies beginning around 2010 .

Here again I turned to one of the JBIS ‘red cover’ interstellar issues, finding Michaud’s paper “Spaceflight, Colonization and Independence” in a 1977 issue. And as I began to work my way through this particular period in interstellar studies, I learned that between 1974 and 1991, the Journal of the British Interplanetary Society had published numerous red cover issues focused on interstellar matters under the editorship at various times of Anthony Martin, J. Hardy and Gerald Groves. When I mentioned the quality of this work to Geoffrey Landis during an interview at NASA Glenn, he told me that JBIS had been the home of advanced concept thinking on deep space for a long time. The red cover issues proved him right.

The problem with JBIS when I was working on my Centauri Dreams book was that, although I had access to an excellent academic library online, the JBIS Interstellar Studies issues with the red covers were, like the rest of the journal’s output, unavailable in full text form. That meant making my way to the local university library, where I quickly became familiar with the red cover issues and worked my way through Project Daedalus, not to mention the numerous studies of interstellar propulsion schemes, communications matters and speculations about alien life.

It’s good to see the British Interplanetary Society moving to make these key papers more accessible. The red cover issues, covering the full range of interstellar studies, are now available by the paper or journal issue directly from the BIS. The Interstellar Studies Index can be accessed for a look at what’s available, with the last Interstellar Studies issue being the August, 1991 journal, where I find a Greg Matloff study on precursor solar sail probes, and Robert Zubrin’s “Nuclear Salt Water Rockets: High Thrust at 10,000 Seconds ISP.” But working through the index pulls up many familiar names, including Michael Michaud’s “A Manifesto for Expansion,” many Robert Forward papers, Giovanni Vulpetti’s work on antimatter, and classic papers that have energized the field, like Matloff’s “Solar Sail Starships: The Clipper Ships of the Galaxy.” The red cover issues are a compendium of the best interstellar thinking of their era and form a key reference for anyone working on these matters today.

Building a Scholarly Infrastructure

I have stacks of printouts of these papers filled with check marks and comments here in my office. I’ve used them over the years, but paging through them I’m reminded that the red cover issues form only a part of what JBIS has published — and continues to publish — on interstellar topics. It was here that Arthur C. Clarke’s famous ‘Challenge of the Spaceship’ paper appeared back in 1946, and where Les Shepherd wrote (in 1952) the first technical paper on interstellar flight. I should also mention, in addition to numerous papers on worldships, the interstellar bibliographies produced by Eugene Mallove and Robert Forward, which built upon and extended the personal Forward bibliographies he had begun compiling while studying engineering at UCLA.

We’re talking about the infrastructure of scholarly investigation, and it’s here that interstellar studies still has to come into its own. The Mallove/Forward bibliographies were not continued because, paradoxically, they became too lengthy to maintain. Both men had ongoing research to pursue, and even as new voices emerged in the field, their subject matter of choice continued to be relatively marginalized. Interstellar specialists worked in their spare time, exchanging letters, talking at conferences, but their effort was and is a subset within the much broader aerospace domain. In that environment, full-time interstellar work is a difficult job description.

The exciting developments in astrobiology and exoplanetary astronomy may change this situation. Interstellar studies could use the kind of targeted collections found in the JBIS red cover issues, and just as significantly, could make use of a yearly interstellar bibliography focusing on the issues that define our encounter with the stars, from propulsion to communications to the philosophical questions raised by potential extraterrestrial contact. All of this is, we hope, fodder for the Tau Zero Foundation as we try to support and encourage an effort that has produced remarkable papers and is building a new infrastructure for growth.

Yeah? Well I read O’niell’s “The High Frontier” when I was 14 and thought that we would be living in space colonies by now. We have to master the art of building space colonies before we can go to the stars.

BTW, the Kepler results show that there aren’t that many “Earths” around and that we have to go 30-50 light years before getting to the nearest one. So, even if we do get that warp-drive, we still need to learn how to build space colonies (which requires a lot of bio-engineering that we have yet to develop).

And in addition to Icarus, Kelvin Long is working to revitalise thinking on manned interstellar travel with the Worldships symposium to be held at the British Interplanetary Society later this summer. This picks up the baton from a number of JBIS papers by Bond, Martin and others.

Personally, I think a longer-term view is more appropriate. As Kurt9 says above, we first have to expand to the interplanetary level before taking on the vastly harder challenge of the stars.

These papers sound both varied and voluminous, not to mention interesting.

Kurt9, I too was a little disheartened by the apparent scarcity of earth-sized planets in the habitable zone implied by the first big Kepler data release. 30-50 light years is an unfathomable distance, at least to me. However, more recently I stumbled upon a rosier assessment of the number of stars which may host small terrestrial sized planets. BTW, Paul, if you were not already aware of the paper to which I am referring, it is by Andrew Youdin of the Harvard-Smithsonian Center for Astrophysics (title is “The Exoplanet Census: A General Method, Applied to Kepler”). It can be a found on the arXiv.org and may be worthy of a thread here on Centauri Dreams given that it concludes that the Kepler data imply essentially all Sun-like stars have planets. Warning: the paper is not light on the mathematics– lots of calculus and non-parametric statistics.

Yes, the Kepler results show that nearly all sun-like stars have planets. The problem is that those results also show that the vast majority of those planets are Neptune-like rather than Earth-like. The one system (Kepler-11) where they were able to characterize the density of those planets, anything bigger than 1.5 Earth radii appears to be low-density enough that they are not rocky planets at all.

Thanks for the reminder — had forgotten about this. I did get to go through Forward’s personal papers at UAH some years back, a fascinating way to spend several afternoons for those who have the chance to get to Huntsville.

@kurt9: Are you taking detection biases into account here? If the majority of terrestrial planets are below, say, 2 Earth masses (judging by the Kepler-11 results this could easily be a possibility) then the detection prospects become even more difficult due to both low transit depths and low radial-velocity amplitudes.

I am a little leery of the assumptions of the Kepler results. Transiting, like Dopler, shifts selects for size and closeness. What we are seeing here is a census of systems that have Super-Earth to Neptune sized planets in close orbits, and for this type of system, it may be rare to have Earthmass planets in the habitable zone. But consider our system, if Kelper looked at it so that the innermost planet produced a transit. It wouldn’t get a result. Mercury would be too small to show up, and it would be extremely unlikely that Venus and Earth would be aligned.
I still put my faith in the fact that smaller sized bodies will be more frequent. My prediction for the most common planetary system around stars will be a system with 4 Ice-giants outside the ice line and 4-6 Mars sized bodies inside it with the innermost planet at a Mercury-like distance.

@david moore: well consider that the sun is a relatively ordinary star, that much is certain. and while we certainly have found quite a number of hot jupiters (because they’re easy to detect) – around our “ordinary star” there are still 4 terrestrial planets. it happened four times in one system.

is that a coincidence or is it because the conditions that led to the formation of one led to all? if it’s the latter then maybe terrestrial planets may be uncommon, but if it’s the former then they should be all over the place. right?

Amanda,
Both Dopler and Transit detections pick up larger planets close to the star. These are the result of a dense long-lived nebula. Dense long lived nebulae produce both large planets and inward migration through gas drag (via Type I and Type II migration). This produces planetary scattering which leads to the preferential ejection of smaller planets and elliptical orbits common in the remainder: the sort of system we pick up with large planets packed close in to the star.

Our system appears to be on the cusp of this type of system with evidence of migration both in and out of Jupiter and Uranus and Neptune swapping orbits.

But we know nothing of star systems with less dense nebulae or systems that have their clouds evaporated early on by the UV of a nearby supergiant. From what we know of planetary formation, these systems would have only small bodies in their inner system, and they appear to be the majority of star systems otherwise we would be getting doppler hits of 80% of systems rather than something more like 10%.

These systems would not form gas giants or experience as much inward migration through gas drag so there would be much less dynamic interaction between planets. Outside of the ice line, the Ice Giants would stay where they formed. Inside of the Ice Line the terrestrial planets would coalesce, but with no massive planet to pump up their eccentricity, there would be a tendency for more, smaller bodies.

If you think of our inner system as being composed of 20 Mars-sized protoplanets, then one had something blow its crust off and it become Mercury, one became Mars, 8 coalesced into Venus and 10 coalesced into Earth. If you were to have a less massive system of say 10 Mars sized protoplanets and no massive giant to stir them up, them you would more likely get the sort of system where there are 6 rocky planets, inside the Ice Line, 3 of Mars mass, a couple of two-Mars mass and one of three-Mars mass. And given the smallish percentage of systems we find with massive bodies in the inner system, I would predict that this will be by far the most common arrangement.

Statistically speaking the Sun is an above average sized star, and while the size of the star does have some bearing on the planetary nebulae, it is only one of many factors. Others, like nebulae metalicity, appear to be more important.

– intermediate metallicity gives an intermediately dense proplyd, giving a planetary system with small, rocky planets on the inside and (sub)giant planets on the outside.

The question then remains where the numerously found systems with super-earths and Neptune/Uranus like subgiants fit in this gradient. Are they intermediate between the high and intermediate metallicities/proplyd densities? Or are they high metallicity systems with much/most of the gas layers of the inner (sub)giant planets blown off?

Has there been a correllative study with regard to the Kepler findings and stellar metallicity?

i loved reading JBIS when i was in my teens (1970s); those were some fearless thinkers, & among them a few ideas which haunt me even today (neon oceans on Pluto, anyone?). i little suspected i would live to see a robot landed on Titan, however.

Spaceman, that paper you referenced looks really powerful, but it seems to require that Kepler’s parameters for likelihood of detection of a transiting planet of a given radius are exactly as they should be in theory. If the authors have a close enough connection to the raw data and the exact details of the programme by which it has been processed to know the truth in that and their maths is good, then we really should put money on most sunlike stars turning out to have close in planets. Given the number of skeptics here we should clean up.

Ronald,
I’m sure that somewhere some has looked at the metalicities of the Kepler planets. It’s probably in their big paper.

I would also look at the paper on debris disked that Paul review on May 4th. The gist of it is that if you have a system that is a billion years old and it still has a dense cometary belt, then this implies no interactions between the major planets as a perturbed giant planet would have scattered the belt. If the cometary belt is undisturbed then the inner system should also be undisturbed and terrestrial planets should have coalesced there. About 16% of all system meet this criterion. Systems with giant planets in the inner system don’t have detectable (i.e. dense) cometary belts. I’ve only given the paper a quick first reading, but it appears to have a lot of other interesting implications on planetary formation. It’s worth a read.

How all this squares with the Kepler team’s estimate that only 2.6% of systems have Earthlike planets and the appearance that there is one rogue Jupiter for every system in the galaxy, I don’t know.

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Charter

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last nine years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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